Intermittent stepwise cooling and warming ameliorate chilling injury and improve quality in postharvest Guifei' mango fruit

Chilling injury (CI) has been a major factor restricting the commercial distribution of mango fruit. In this study, an innovative technology termed intermittent stepwise cooling and stepwise warming (ICW) was employed to investigate its effect on CI in mango fruit by evaluating ripening- and cold tolerance-related parameters. Results showed that ICW exposure maintained normal ripening in mango fruit during refrigeration at 5 degrees C and subsequent shelf storage at 20 degrees C, as manifested by increased ethylene production and respiration rate and accelerated changes in softening, color, soluble solid content, titratable acidity and chlorophyll and carotenoid contents. ICW inhibited increases in electrolyte leakage rate (ELR) and production of reactive oxygen species (O-2(-). And H2O2) and malondialdehyde (MDA). ICW resulted in higher activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR), while promoting more accumulation of total phenolics, flavonoids, ascorbic acid and glutathione. In addition, the expressions of genes (MiICE1, MiCBF1 and MiCOR413) encoding cold-responsive factors were upregulated in response to ICW. These physio-biochemical changes conferred by ICW contributed to enhanced cold tolerance and reduced CI in mango fruit. The results indicate that ICW application could be a potential strategy for postharvest refrigeration of 'Guifei' mango fruit.